Drill with automatic feed and quick retraction



May 19, 1970 D. P. JUHASZ ET L 3,

DRILL WITH AUTOMATIC FEED AND QUICK RETRACTION Filed Nov'. 29, 1967 2Sheets-Sheet l DAN/6L .2 Jw-msz \o Lu/s H. BoHoQQus'Z OWM VQTZM May 19,1970 DRILL WITH Filed Nov. 29, 1967 D. P. JUHASZ ET AL AUTOMATIOFEED ANDQUICK RETRACTION 2 Sheets-Sheet 2 N 1 5995 6. 711N052 g [NVENTORS 9 Vfl,

United States Patent 3,512,434 DRHJL WITH AUTOMATIC FEED AND QUICKRETRACTION Daniel P. Juhasz, Gardena, Luis A. Bohorquez, Inglewood, andPierre G. Vindez, Redondo Beach, Calif., assignors to ZephyrManufacturing Co., Inc.Manufacturing Division, Inglewood, Califi, acorporation of California Filed Nov. 29, 1967, Ser. No. 686,485

Int. Cl. B23b 45/04 US. Cl. 777 7 Claims ABSTRACT OF THE DISCLOSURE Theapplication discloses portable power drills with which various types offixtures and clamping devices can be used in conjunction with the drilland work to secure the two together for a given drilling operation, thedrill embodying a drill spindle, a power gear train for rotativelydriving the spindle, and a feed gear train for advancing and retractingthe spindle, together with automatic means for controlling the feed andretraction of the spindle and an automatic means for stopping the motor.

The invention relates generally to drills and particularly to portableand hand-held drills, such as finger drills and the like, and moreparticularly to mechanisms for advancing and retracting a drill spindle.

An object of the invention is to provide a new and improved feedmechanism for a drill spindle or the like embodying novel gear means forrotating, advancing, and retracting the spindle. In this connection itis an object to provide such means which rapidly retracts the spindlewhile continuing to rotate it in the normal drilling direction with theconsequent advantages of this type of mechanism over a known type whichreverses the rotation of the spindle upon retraction and has a highincidence of drill breakage.

Another object is to provide automatic means for reversing the axialmovement of the drill spindle after it has advanced a predetermineddistance, thereby enabling the drilling of blind holes without exceedingthe required depth of the hole.

Another object is to provide novel means for controlling the feed andretraction of the drill spindle including means for preadjusting thelength of the feed stroke and the relative position thereof with respectto the housing.

Still another object is to provide drill mechanisms of the typeindicated which can utilize hollow spindles so that drilling lubricantcan be circulated therethrough and through the drill to the work face.

These and other objects will be apparent from the drawings and thefollowing description. Referring to the drawings:

FIG. 1 is an isometric view of a portion of a drill embodying theinvention;

FIG. 2 is a central longitudinal vertical sectional view on line 22 ofFIG. 1, but on a larger scale;

FIG. 3 is a sectional plan view on line 3-3 of FIG. 2;

FIG. 4 is an enlarged detail view of a portion of the apparatus of FIG.2 in the same plane as that figure;

FIG. 5 is a fragmentary sectional view on line 5--5 of FIG. 4;

FIG. 6 is a fragmentary cross sectional view on line 6-6 of FIG. 2;

FIG. 7 is a longitudinal sectional view of a modification showing anautomatic feed and retraction means;

FIG. 8 is a fragmentary sectional view on line 8-8 of FIG. 7;

3,512,434 Patented May 19, 1970 FIG. 9 is a sectional view on line 9-9of FIG. 8;

FIG. 10 is a fragmentary sectional view in the same plane as FIG. 7,showing a portion of the apparatus;

FIG. 11 is a fragmentary sectional view on line 1111 of FIG. 10.

More particularly describing the invention, referring first to FIGS. l6,numeral 11 generally designates a finger drill, and this includes asuitable motor 12 and a housing 14 in which the drill spindle is mountedand which contains the mechanism for driving, feeding and retracting thespindle. The housing has a main body 15 with an enlarged tubular end -16having an internally threaded bore 17 in which the motor 12 is mountedas shown. Forwardly of this the housing body extends generally axially(much like a straight finger) but somewhat offset from the axis of thetubular end 16. The housing body is open-topped but covered by a plate18 reniovably held by screws 19. A spindle 20 extends through thehousing from top to bottom and is adapted to mount a drill or drill bit22, shown attached to the lower end of the spindle in FIG. 2 by anadapter 23.

Betweenthe motor and the spindle we provide means for advancing andretracting the spindle axially and means for simultaneously rotativelydriving it. In general the means includes two sets of gears or two geartrains which will be termed a drive gear train and a feed gear train 26.The drive gear train has a combination or special gear 27 (which may bemade in two pieces suitably interlocked if desired) at the motor endthat is mounted for rotation about a screw 28 with needle bearings 30between the parts. The screw serves to secure a plug 31 in a bore 32 andcounterbore 33 in the housing body and includes a threaded inner endsection 34 received in a threaded bore 35 in the housing body. Gear 27has a beveled gear face 38 for engagement with a beveled gear 40 on theend of the motor shaft 41 of the motor and consequently is driventhereby whenever the motor is operating. At the other end of the drivegear train is a drive gear 43 mounted in a bearing 44 secured in a bore45 and counterbore 46 of the housing body. Gear 43 has a bore 47therethrough of suflicient diameter to freely receive and pass thespindle so that the same may be moved axially therethrough in advancingand retracting the spindle. The driving connection between the drivegear and the spindle is shown as comprising two splines 50 (FIG. 6)integral with gear 43 and extending into longitudinal grooves or keyways51 in the periphery of the spindle, the parts fitting just loose. enoughto permit of relative axial movement.

Between the drive gear and the combination gear are a plurality of idlergears designated 53, 54 and 55. Gears 53 and 54 are mounted on pins 56and 57 respectively which are mounted in the housing as best seen inFIG. 2. Gear is mounted on a hollow shaft 60 that is mounted in a bore61 provided in the bottom wall 62 of the housing body. In each casebearings 63 are provided for the gears. With this construction it willbe apparent that the spindle is rotatively driven in one direction atall times that the motor is operating.

Turning now to the feed gear train, at the outer end of the housing weprovide a feed gear in the nature of a feed nut which is mounted in abearing 71 provided in a bore 72 in the cover plate 18 of the housingand partially within a counterbore 73 in the drive gear 43, the feedgear having an extension 74 which rotatively fits in said counterbore.The feed gear has an internally threaded bore 76 to accommodate thespindle which is provided with corresponding external screw threads 77.Thus relative rotation between the feed gear and the spindle will causeaxial movement of the spindle.

At the motor end of the feed gear train is a coupling gear 80 whichnormally engages through end teeth 81 with similar end teeth 82 on theadjacent end of gear 55 and when so engaged is driven thereby. Betweenthis gear and the feed gear are two idler gears designated 83 and 84which are mounted on the aforementioned pins 56 and 57, respectively.The over-all ratio of the feed gear train is slightly different fromthat of the drive gear train so that when both gear trains are driven,as when the parts are in the position shown in FIG. 2, the speed ofrotation of the feed gear will be sufficiently greater than that of thedrive gear to effect a gradual advance of the spindle.

In order to provide for rapid and positive retraction of the spindle,while continuing to drive the spindle rotatively in the original orgiven direction, we mount the coupling gear 80 on an axially movableshaft 86 which has a reduced inner end section 87 that is slidablyreceived in the hollow shaft 60. Above this is a flange 88 and abovethis a main cylindrical section 89 which is interrupted by a groove 90for a retainer ring 91 to hold the gear in place. The upper end of theshaft is provided with an operating lever 94 and when this is in theposition of FIG. 2, the shaft is locked in the inner position so thatthe coupling gear is in driven relation with the combination gear, theparts being releasably held in this position by means of a pin 95 in thehousing body which is received in a spiral-shaped slot 96 (FIG. in thedepending hub 97 of the lever the fits within a cylindrical cavity 98 inthe mold. A compression spring 100 in the space 101 yieldably urges thelever and shaft upwardly. When the lever is turned to release the shaftand permit it to move upwardly under the influence of the spring to theposition shown in FIG. 4, an upper radially grooved annular end face 103of the coupling gear engages a coupling brake ring 104 having a serratedend face 106 adapted to mate with face 103 thereby stopping its rotationand operation of the feed gear train. Consequently, since the spindlewould be threaded oppositely with respect to the direction of itsrotation, and it is still being rotated in the original direction, itrapidly retracts through the now stationary feed gear 70.

During retraction of the spindle, if an abutment on the spindle, such asthe adapter 23 (FIG. 2), strikes the housing, slippage can occur betweenthe coupling gear and the brake ring as spring 100 yields so that thefeed gear can then rotate with the spindle and the spindle will not besubjected to any further retraction force.

It is to be understood that various types of fixtures and clampingdevices can be used in conjunction with the drill and the work to securethe two together for a given drilling operation.

We may also provide for automatic control of the feed and retraction ofthe spindle and one means for accomplishing this is shown in the form ofthe invention illustrated in FIGS. 7-11 wherein a finger drill withautomatic control means is shown. Referring to these figures, numeral120 designates an air-driven motor and numeral 121, the housing for theapparatus of the invention. The motor has a threaded cylindrical end 122which is mounted in a threaded counterbore 123 at the tubular end 124 ofthe housing. The motor is shown provided with a bevel gear 125 on themotor shaft 126 and this serves to drive a drive gear train 128 which isgenerally similar to the one previously described, and, under certaincircumstances, a feed gear train 130 which is also generally similar tothe one previously described. In view of the similarities, theconstruction will not be described in minute detail. However, referringto the parts, they include the exteriorly threaded spindle 132 with thelongitudinal grooves 133 that are received for axial movement through adrive gear 134 that is driven whenever the motor is operating throughthe medium of idler gears 135 and 136 and 137, the latter meshing with acombined gear 138 comprising a spur gear 140 and a bevel gear 141 whichare locked together for rotation as a unit. Gear 138 is driven by thebevel gear 125 of the motor. The drive gear 134 has two integral splines(not shown) similar to the drive gear of the previously described formof the invention, which are received for slideable movement in thegrooves 133 of the spindle.

The feed gear train includes the interiorly threaded feed gear 142 whichreceives the spindle, the idler gears 143 and 144 and a coupling gear145 which normally is held engaged with gear 137 when the tool isoperating and the drilling operation is being performed. However, inthis form of the invention, the coupling gear 145 is mounted on anaxially movable shaft that is moved toward gear 137 and held inengagement therewith by fluid pressure, air being the desired fluid. Toaccomplish this, one end of the shaft has a head or piston 152 providedwith a peripheral sealing ring 153, the piston fitting in a cylindricalbore 154 in the housing which is closed by a plug 155.

The gear 145 shifts axially with the shaft, being mounted on a bearing157 that is restrained at one end by a ring 158 on the shaft andyieldably held thereagainst by compression spring 160.

Mating serrated faces 161 are formed on the gears 137 and 145 toestablish a driving connection between the parts when they are held inengagement by means of air pressure in the cylinder 154. When the airpressure is relieved, spring moves the shaft in a direction to disengagegears 137 and 145 and cause gear 145 to engage a coupling or brake ring162, the parts being provided with mating annular end faces 163 whichcomprise a radially serrated surface on one member and radially groovedsurface on the other.

For the purpose of controlling the device automatically, stop means areprovided on the spindle and, for convenience, such means has been shownas a pair of nuts on one side of the housing and a pair 171 on the otherside thereof. These can be adjusted and set to limit and position thestroke of the spindle, and they are designed to work in conjunction witha valve system designated generally by numeral 172 that controls thesupply of air to the cylinder 154. In the housing we provide a bore 174which receives a cylindrical valve 175 movable axially therein. Thevalve has enlarged end portions 176 and 177 and radially reducedintermediate sections 178 and 179 separated by three flanges 180 betweenwhich are seal rings 181. Another flange 182 adjacent section 176defines a groove therewith to receive a seal ring 183. The annular spacebetween the seal rings 181 and 183 serves to connect cylinder 154through a suitable port and passage labeled CYL. (FIG. 9) and otherpassage means in the housing either to air under pressure through a portand passage labeled PRES. and other means not shown or to connect thecylinder to atmosphere or exhaust through a port and passage labeledEXH. and other associated means not shown.

In the operation, assuming the parts are in the position of FIGS. 7 and9, air is supplied to cylinder 154 so that the feed gear train is drivenand the spindle is being advanced. After the spindle has advanced thepredetermined amount, stop nuts 170 on the spindle will engage an arm186 on the end of the valve 175 and the further advancement of thespindle will move the valve the limit of its travel. This relieves thepressure on the piston 152 connecting it to exhaust and allows spring160 to disengage coupling gear 145 from gear 137 and move it intoengagement with coupling ring 162, thereby stopping the feed gear trainand causing rapid retraction of the spindle. Upon retraction, when stopnuts 171 on the spindle engage an arm 185 at the other end of the valve,the valve will be returned to normal feed position.

One advantage of the construction is that the spindle can be made with afluid passage therethrough to deliver a suitable fluid to the drill, itbeing only necessary to provide a rotary fitting in the end of thespindle for the attachment of a supply hose.

By way of example of a modification coming within the scope of theinvention, we contemplate that the drive and feed gears might beinterchanged in the two gear trains, that is, the feed gear might bedriven at all times and the drive gear coupled and uncoupled from themotor. It would then be necessary to have the spindle threaded in thesame direction as the direction of rotation thereof when driven by thedrive gear so that when the latter is stopped, the spindle will retract.Also, in this case, the drive gear will have to be driven slightlyfaster than the feed gear to effect the advance of the spindle.

What is claimed is:

1. An automatic feed and quick retraction drill assembly, comprising ahousing, an externally screwthreaded spindle adapted to mount a drillbit, a spindle drive train in the housing adapted to be motor-driven andincluding a drive gear receiving said spindle and keyed thereto, saidspindle being axially movable through said drive gear, a spindle feedtrain in the housing including an internally threaded feed gearthreadedly receiving said spindle, an axially shiftable coupling gearforming part of said feed train for establishing a driving connectionbetween said drive and feed trains and movable to disengage saidconnection, a stationary brake ring for restraining said feed trainengageable by said coupling gear when the same is not coupled to saiddrive train, and means for shifting said coupling member including afluid motor of the piston-cylinder type for moving said coupling memberin on direction and spring means for returning the same.

2. The automatic feed and quick retraction drill assembly set forth inclaim 1 in which said fluid motor is connected into a fluid systemincluding a valve controlling flow of fiuid to said fluid motor and inwhich adjustably positionable means is provided on said spindle operablyassociated with said valve.

3. An automatic feed and quick retraction drill assembly, comprising ahousing, a spindle having external screw threads and adapted to mount adrill bit, a first gear train in the housing including a drive gearreceiving said spindle and keyed thereto, said spindle being axiallymovable through said drive gear, said first gear tram being adapted tobe driven by a motor, a second gear train in the housing including aninternally threaded feed gear threadedly receiving said spindle, saidsecond gear train including an axially shiftable coupling gear movableinto and out of driven relation with said first gear train, a brakemember for restraining said coupling gear against rotation when engagedby the coupling gear when the same is not in driven relation with saidfirst gear train and thereby cause retraction of the spindle, shiftmeans engageable with said coupling gear for moving the same betweensaid first gear train and said brake means, and spring means effectivelyinterposed between the housing and said coupling gear yieldably urgingsaid coupling gear into engagement with said brake means enabling saidsecond gear train to rotate with the spindle against the restrainingeffect of said brake means when said spindle is prevented fromretracting.

4. The automatic feed and quick retraction drill assembly set forth inclaim 3 in which said spindle is provided with a stop limitingretraction of the spindle.

5. The automatic feed and quick retraction drill assembly set forth inclaim 3 in which said coupling gear is mounted on an axially movableshaft having an actuating lever and means for releasably locking it in aposition such that said coupling gear is in operative engagement withsaid first drive train, and in which spring means between lever andhousing associated with said shaft urges the same in a direction todisengage said coupling gear from said drive element and urges it toengage the brake means.

6. An automatic feed and quick retraction drill assembly, comprising ahousing having an aperture therethrough, an externally screw-threadedspindle extending through said aperture adapted to mount a drill bit, afirst gear train mounted in said housing including a drive gearreceiving said spindle and keyed thereto, said spindle being axiallymovable through said drive gear, said first gear train being adapted tobe driven by a motor, a second gear train including an internallythreaded feed gear threadedly receiving said spindle, said second trainincluding a coupling gear, an axially movable shaft carrying saidcoupling gear, a brake ring in said housing beyond one end of saidcoupling gear, said shaft being shiftable axially selectively to causesaid coupling gear operatively to engage said first drive train or toengage said brake ring, interengaging means on said housing and saidshaft for releasably locking said shaft in position with said couplinggear in engagement with said first drive train, and spring meansinterposed between said housing and said shaft yieldably urging saidshaft in a direction to cause said coupling gear to engage said brakering.

7. 'In a finger drill, an elongated housing having a transverse openingat one end, an externally threaded drill spindle extending through saidopening, an internally threaded feed gear in the housing receiving saidspindle, a drive gear in the housing receiving said spindle and keyedthereto, said spindle being movable axially through the drive gear, amotor mounted at the other end of the housing, a drive gear train drivenby said motor and extending between the motor and spindle and includingsaid drive gear, a feed gear brake member, means for selectivelycoupling said feed gear to said drive gear train or said brake memberincluding a shiftable coupling element, a stop member provided on saidspindle, and means responsive to engagement by said stop member forshifting said coupling element.

References Cited UNITED STATES PATENTS 434,576 8/ 1890 Wyman 77-34.72,791,922 5/1957 Robinson 77344 3,124,817 3/1964 Mosier 7734.7 XR3,421,392 1/ 1969 Bangerter et al. 777 3,429,206 2/1969 Quackenbush7734.7

FRANCIS S. HUSAR, Primary Examiner US. Cl. X.R.

